1. Field of the Invention
The present invention relates to a disposable needle head assembly to be used with a standard syringe body, the needle head assembly being especially adapted to contain and shield a hypodermic needle after use, thereby preventing accidental injury as a result of the hypodermic needle and insuring automatic protection after use of the hypodermic needle.
2. Description of the Related Art
With the increase in the number and severity of numerous contagious, and potentially deadly diseases, such as HIV, and the more informed nature of our society with regard to how these diseases are transmitted, particular attention has been given to the safety requirements associated with the use of hypodermic needles. These needles, after use on sick patients, become contaminated and pose a significant threat to medical attendants, as well as any other individual who may come in contact with a used syringe in the trash or an improperly discarded location. As a result of this pressing need, there have recently been numerous patented inventions directed towards providing a safety shield for a hypodermic needle. Of the protective covers which utilize springs and/or slot arrangements in their design, a majority, such as those recited in Bayless, U.S. Pat. No. 4,863,434, Bayless, U.S. Pat. No. 4,850,977, Burns, et al., U.S. Pat. No. 4,966,592, and Morgan, U.S. Pat. No. 4,923,447, incorporate a protective assembly as part of an entire syringe assembly. Further, they require manual operation of the protective device, which will not protect against carelessness and will not immediately cover the needle, but will rather necessitate that an individual activate the protective covering of a potentially contaminated needle. In addition to being manually effectuated, common medical practice utilizes solely a disposable syringe tip, enabling the syringe body to be reused, thereby making protective coverings which are formed as part of an entire syringe to be non-effective. As a result of the common use of disposable syringe tips, rather than an entire disposable syringe, protective coverings such as those disclosed in Vaillancourt, U.S. Pat. No. 4,725,267 and Perry, U.S. Pat. No. 4,813,940 have incorporated spring activated protective assemblies as part of the syringe tip. Of these references, only Perry does not require manual extending of the protective covering after the needle has been used. The 14 reference to Perry, however, requires initial manual positioning 15 and is adapted to be fitted on a needle after medication to be 16 injected has been drawn into the needle. Accordingly, the protective cover of Perry is not formed integrally with the needle tip, requiring manual positioning which can be dangerous when attempting to thread a sharp needle into its protective casing. Further, careless or lazy users would be able to not use the protective casing, thereby lessening the overall safety effectiveness of the assembly. As a result, it would be highly beneficial to have a disposable needle head assembly which comes protectively encased so as to make it safe to attach to the syringe body, enables the needle tip to be visible and exposed prior to injection, thereby enabling a more accurate injection, and automatically becomes engaged in a protective orientation as a result of the normal use of the needle, that normal use including drawing medication from a vial as well as injecting a patient. The device of the present invention is designed specifically to meet these pressing needs for a needle whose tip will be exposed only when purposefully required and will minimize accidents due to carelessness by ensuring that the needle is protected automatically and not as a result of affirmative steps taken by a user.